Bending Simulation Research Articles

Computational and experimental mechanical characterization of a novel corneal implant for the treatment of keratoconus

Aims/Purpose: Current treatment options of keratoconus have several limitations. These limitations have been addressed by developing a novel nitinol GROSSO® implant, that restores the physiological curvature of the cornea by virtue of a dome‐shaped design. Its minimally invasive implantation requires accurate assessment of the mechanical properties, investigated here both experimentally and computationally.Methods: Bending of two opposite edges of the implant is necessary for its implantation in the intracorneal pocket. Bending was conducted experimentally at 37°C using a DMA Q800 (TA Instruments) with a thermal chamber and a cell load of 18 N to obtain force‐displacement curves. A computational model of the real implant was reconstructed from microcomputed tomographic acquisitions (Phoenix v|tomo|x m, resolution: 1μm). The mechanical behaviour of the implant was modelled by implementing a superelastic constitutive law with material parameters obtained from experimental tensile tests of the nitinol, which also determined the plastic permanent deformation value. Finite element analysis of the bending simulation was performed in Abaqus (Dassault Systèmes Simulia Corp.) to obtain the bending force (BF) and assess the absence of permanent deformation.Results: A good agreement between the experimental (0.09 N) and computational tests (0.08 N) in terms of BF was observed. The computational simulation highlighted that the maximum principal strain value during bending was 10.8%, i.e. below the limit strain for plasticity of 12%.Conclusions: The GROSSO® implant can be safely bent during implantation with minimal effort, as the force applied does not exceed 0.1 N. The ongoing validation of the computational model will enable a cost‐effective prediction of macro‐scale mechanical properties and compliance with relevant standards and regulatory requirements. Additional critical scenarios and the remodeling effect imposed by the implant on corneal tissue will be the subject of future investigations.

A Method for Calculating the Bearing Capacity of Basic Members of an Underground Concrete-Filled Steel Tube Supporting Arch with a D-Shaped Cross Section

High-strength concrete-filled steel tube (CFST) arches have been widely applied in underground engineering, among which there are special-shaped arches such as D-shaped sections. At present, most studies have concentrated on members with square or circular sections, while relatively few studies have been conducted on D-shaped section members. In this study, firstly, D-shaped sections were initially transformed into sections with a part square and part elliptical shape using an equivalent section method. The formulas for the axial compression and pure bending bearing capacities of the basic D-shaped CFST members were deduced using unified theory, and the bearing capacity of the D-shaped members was calculated in a given case. Secondly, numerical simulations of axial compression and pure bending of the basic CFST members with three section types (square, circular, and D-shaped) were carried out using ABAQUS software. To ensure the reliability of the numerical simulations, the concrete damage constitutive model and the elastic–plastic model were adopted to simulate the core concrete and the steel tube, respectively. In the results, the axial compression and pure bending bearing capacities of the D-shaped section obtained via theoretical calculation were 2339.6 kN and 84.8 kN·m, respectively, while the results obtained via numerical simulation were 2335.8 kN and 85.4 kN·m, respectively, which were relatively close. Among the three section types of members, the D-shaped members had the highest axial compression bearing capacity, which was 1.45% and 4.58% higher than those of the circular and square section members, respectively. However, their bending moment bearing capacity was relatively low. The stress distribution of the D-shaped members presented a characteristic where the circular part dominated, and the stress transfer effect of the members was favorable. In practical engineering, when the surrounding rock pressure is high and evenly distributed, D-shaped section arches can be selected, and increasing the proportion of the square area in D-shaped sections can enhance the overall flexural capacity of arches.

Modeling and Simulation of Bending, Tensile and Impact Loads of Reinforced Thermosets with Carbon Fiber Fleece

Modeling and Simulation of Bending, Tensile and Impact Loads of Reinforced Thermosets with Carbon Fiber Fleece

Fracture Criterion Calibration and Finite Element Simulation in SUS304 Stainless Steel.

In order to calibrate the ductile fracture criterion in SUS304 stainless steel, four tensile samples were designed, their finite element models were established, and uniaxial tensile tests were carried out. The simulation results were compared with the tests. Due to the limitations of finite element software, only a few criteria can be solved in MENTAT of MSC.MARC 2013. In order to make the ductile fracture criteria universal, the HYPELA2 subroutine was used to write the ductile fracture criteria, and the three-point bending simulation was used to verify the ductile fracture criteria program. Finally, the calibration results of different fracture criteria are compared with the test results. The results show that the error between the finite element results of four samples and the test results is small, which verifies the feasibility of the finite element model. Based on the Oh criterion, the correctness of HYPELA2 subroutine development is verified by a three-point bending simulation. In the SH sample, the Freudenthal, C-L, and LeRoy criteria have a better prediction ability, and the prediction error of other criteria is relatively large. All the criteria have a strong prediction ability for the NT20 and CH05 samples.

The Study and Application on Ductile Fracture Criterion of Dual Phase Steels During Forming

High-strength steel exhibits complex fracture behavior due to the interplay between shear and necking mechanisms during stamping and forming processes, posing challenges to achieving the dimensional accuracy and reliability demanded for automotive body panels. Existing prediction methods often fail to simultaneously account for both tensile and shear fracture characteristics, thereby limiting their predictive accuracy under diverse stress conditions. To address this limitation, we propose a ductile fracture criterion that integrates both tensile and shear mechanisms, calibrated using a single tensile–shear test to facilitate practical engineering applications. This study investigates the fracture characteristics of DP780 dual-phase steel through numerical analysis and tensile–shear experiments. The findings establish a relationship between stress triaxiality and ultimate fracture strain across varying stress states, represented by the B–W curve. Simulations reveal distinct stress triaxiality behaviors under different loading conditions: under uniaxial tensile loading, triaxiality ranges from 0.33 to 0.6, with fracture strain decreasing monotonically as triaxiality increases. Under shear loading, triaxiality ranges from 0 to 0.33, with fracture strain increasing monotonically as triaxiality rises. Additional bending simulations validate that this criterion, along with the B–W curve, reliably predicts the fracture behavior of DP780, offering an effective tool for predicting fracture in dual-phase steels during stamping and forming processes.

Biomechanical analysis of nickel-titanium (NiTi)–cobalt-chromium (CoCr) hybrid-braided dense-mesh stents for carotid artery stenosis

This study investigates NiTi-CoCr hybrid carotid artery stents to enhance mechanical properties over NiTi-only designs. Different configurations (24NiTi, 20NiTi-4CoCr, 16NiTi-8CoCr, and 12NiTi-12CoCr) were evaluated through radial compression and bending simulations. The 12NiTi-12CoCr stent showed the highest radial support (39.37 N) and increased bending strength by 77.96%. When modeled in a stenotic artery, this stent reduced stenosis from 81.52% to 29.33% and improved blood flow dynamics, alleviating high-pressure zones and balancing wall shear stress. These results suggest that CoCr wires improve stent performance, with the 12NiTi-12CoCr stent offering significant biomechanical and hemodynamic benefits.

Flexural behaviors of asymmetric Re-entrant auxetic honeycombs

A family of negative Poisson's ratio honeycombs with asymmetric base units and potential applications in civil and marine industries are introduced by introducing asymmetricities to the geometry of regular re-entrant unit cell. These structures, namely the single symmetry-broken re-entrant (SSR), double symmetry-broken re-entrant (DSR), and hybrid symmetry-broken re-entrant (HSR) honeycomb lattices, are fabricated through fused filament fabrication and subjected to experimental three-point bending (TPB) experiments and simulations. The novel designs showcase exceptional specific energy absorption (SEA) attributes compared to the regular metamaterial, with the SSR structure exhibiting a remarkable 147.2% higher SEA. The asymmetric metamaterials also demonstrate higher flexural modulus (Ef) compared to the benchmark design, with the SSR and DSR models boasting approximately 29% and 19% higher Ef, respectively. Studies on design parameters show that internal angle of unit cells that creates the asymmetricity affects the flexural performance of the unique auxetic honeycombs, significantly. Finally, parametric investigation on out-of-plane bending of the honeycombs showed the dominance of all asymmetric-unit honeycombs over the benchmark due to having organized self-contact regions. The SSR and DSR structures own about 51% and 39% higher SEA than the benchmark honeycomb under out-of-plane TPB, respectively.

Thermal Bending Simulation and Experimental Study of 3D Ultra-Thin Glass Components for Smartwatches.

The heating system is an essential component of the glass molding process. It is responsible for heating the glass to an appropriate temperature, allowing it to soften and be easily molded. However, the energy consumption of the heating system becomes particularly significant in large-scale production. This study utilized G-11 glass for the simulation analysis and developed a finite element model for the thermal conduction of a 3D ultra-thin glass molding system, as well as a thermal bending model for smartwatches. Using finite element software, the heat transfer between the mold and the glass was modeled, and the temperature distribution and thermal stress under various processing conditions were predicted. The findings of the simulation, when subjected to a numerical analysis, showed that heating rate techniques significantly affect energy consumption. This study devised a total of four heating strategies. Upon comparison, optimizing with heating strategy 4, which applies an initial heating rate of 35 mJ/(mm2·s) during the initial phase (0 to 60 s) and subsequently escalates to 45 mJ/(mm2·s) during the second phase (60 to 160 s), resulted in a reduction of 4.396% in the system's thermal output and a notable decrease of 7.875% in the heating duration, respectively. Furthermore, a single-factor research method was employed to study the forming process parameters. By comparing the numerical simulation results, it was found that within the temperature range of 615-625 °C, a molding pressure of 25-35 MPa, a heating rate of 1.5-2.5 °C/s, a cooling rate of 0.5-1 °C/s, and a pulse pressure of 45-55 Hz, the influence on residual stress and shape deviation in the glass was minimal. The relative error range was within the 20% acceptable limit, according to the experimental validation, which offered crucial direction and ideas for process development.

The effect of ice shelf rheology on shelf edge bending

Abstract. The distribution of pressure on the vertical seaward front of an ice shelf has been shown to cause downward bending of the shelf if the ice is assumed to have vertically uniform viscosity. Satellite lidar observations show that many shelf edges bend upward and that the amplitude of upward deflections depends systematically on ice shelf thickness. A simple analysis is presented showing that upward bending of shelf edges can result from vertical variations in ice viscosity that are consistent with field observations and laboratory measurements. Resultant vertical variations in horizontal stress produce an internal bending moment that can counter the bending moment due to the shelf-front water pressure. Assuming a linear profile of ice temperature with depth and an Arrhenius relation between temperature and strain rate allows derivation of an analytic expression for internal bending moments as a function of shelf surface temperatures, shelf thickness and ice rheologic parameters. The effect of a power-law relation between stress difference and strain rate can also be included analytically. The key ice rheologic parameter affecting shelf edge bending is the ratio of the activation energy, Q, and the power-law exponent, n. For cold ice surface temperatures and large values of Q/n, upward bending is expected, while for warm surface temperatures and small values of Q/n downward bending is expected. The amplitude of bending should scale with the ice shelf thickness to the power 3/2, and this is approximately consistent with a recent analysis of shelf edge deflections for the Ross Ice Shelf. These scaling relations should help guide fully two-dimensional numerical simulations of shelf bending.

Coupling theoretical analysis and FE framework for revealing the size effect on the deformation characteristics of 304 stainless steel microtubes manufactured via free-bending forming technology

The current study on free bending focuses on traditional macroscopic tubes and profile components. Nevertheless, as the geometric size of the tube decreases, the resulting size effect affects the free bending deformation behavior of the microtube in the less constrained state. In this investigation, a constitutive model of microtubes considering the surface layer model was established. The corresponding model parameters were determined by fitting the flow curves of surface single crystals and internal polycrystals. According to the principle of free bending, the springback internal bending moment of the microtube was derived to explain the phenomenon whereby the bending radius of the microtube decreases with decreasing size factor. With decreasing size factor, the influence of the surface layer grains on the bending behavior of the microtube becomes more intense. Furthermore, by comparing the results of the microscale free bending experiment and simulation, it can be concluded that the material properties of microtubes in the finite element (FE) simulation should be defined based on the surface layer and inner layer. With decreasing microtubule size factor, the bending radius of the tube decreases, and the wall thickness changes more significantly. The cross-sectional distortion of the microtubes decreases with increasing grain size and wall thickness. This study explored the feasibility of the free bending process to achieve bending of microtubes and revealed that the size effect on the deformation behavior of microtubes should be considered in the microscale free bending process.

Macro-meso cracking inversion modelling of three-point bending concrete beam with random aggregates using cohesive zone model

An accurate description of concrete crack propagation is essential to practical engineering. In this paper, the cohesive zone model (CZM) is used to investigate the macroscopic mechanical properties and the microscopic crack damage behavior of concrete beams in the three-point bending test. Five key factors controlling the cracking of cohesive elements, namely mode I fracture energy, mode II fracture energy, shear strength, tensile strength, and elastic modulus (stiffness), are subjected to parametric examinations. Based on macro-mechanical properties and micro-cracking, the test results and parametric models of specimens are inversely analyzed. The applicable parameter range of control factors in the three-point bending simulation is obtained. Considering the quantitative aggregate information of specimens with different mix proportions, three computation models with different aggregate areas are established. The quantitative results of crack propagation are derived by applying the parameter range. Finally, the accuracy of the parameter range is validated based on the simulated and experimental mechanical properties and quantitative results of cracks.

Towards high-accuracy axial springback: Mesh-based simulation of metal tube bending via geometry/process-integrated graph neural networks

Springback has always been a stubborn defect that affects the axial accuracy of metal bending. The finite element simulation of springback enables effective control and precise compensation to improve the forming quality. Affected by the material, size, and forming process, the generation pattern of the springback defect remains further exploration. Graph-based deep learning techniques support differentiable high-dimensional physics simulations with significantly lower computational resources and comparable accuracy. In this paper, a framework based on geometry/process-integrated Graph Neural Networks (GNN) is presented for simulating axial springback of mesh-based metal bending, with a specific focus on the tube bending. The framework adopts an encode-process-decode structure, equipped with parallel graph network blocks and data augmentation strategy, to capture the axial springback information with high fidelity in a form of mesh. Comparative experiments reveal that our framework achieves an accuracy comparable to that of finite elements method, yielding an average nodal error below 1 mm and outperforming three representative GNN baselines. The framework remarkably enhances the simulation efficiency, exhibiting a four-order-of-magnitude improvement on CPU and a six-order-of-magnitude improvement on GPU compared to finite elements method. Furthermore, we successfully apply the proposed framework to simulate the springback of plate V-bending, showcasing its robust generalization ability. These results illustrate the capability of our GNN framework to achieve the accurate and real-time springback simulation, with significant implications for digital twin development and bent tube quality optimization.

P‐171: Research on Improving the Bending Ability of Foldable AMOLED Mobile Screen by Overlaying FMLOC and COE Technology

The market development trend of foldable AMOLED screen is introduced in the article, and then the core links of the industry chain of foldable mobile phones is drawn off. Furthermore, that improving the bending ability is an urgent problem to be solved in achieving lightweight is proposed. Based on this demand, a specific structural scheme and a complete set of bending ability evaluation methods to achieve lightweight affect are put forward. By combining bending simulation and product failure test, the mechanism is analyzed, and also, the main and secondary factor affecting bending ability are proposed. After that, a standardized improvement system for bending ability, including optimization of membrane quality, structural optimization, and process optimization, is validated and applied. On condition that an average bending radius of 1.5mm for Panel and 1.3mm for MDL are achieved ultimately, that has reached the international leading level. Moreover, based on the stress simulation research, a nonlinear model relationship between the strain of the TLD film layer (SiNx) and the clamp distance, which is a key factor affecting the bending ability and can predict the bending ability, is established. Finally, the future development direction and research direction of improving the bending ability of foldable AMOLED screen are prospected.

Effects of differential hardening on energy absorption prediction of AA6061-T6 thin-walled rectangular tube

In this study, the energy absorption characteristics and deformation modes of AA6061-T6 thin-walled rectangular tube are investigated experimentally and numerically under different crushing conditions, including axial crushing, three-point bending and oblique crushing. Mechanical tests are carried out on four specimens of uniaxial tension, uniaxial compression, shear and plane strain tension along different loading directions for AA6061-T6. Besides, the effect of differential hardening behavior on the energy absorption prediction of AA6061-T6 rectangular tubes is illustrated by comparing Lou2022, von Mises and SY2009 functions. The mechanical experiment results indicate that AA6061-T6 shows obvious anisotropy, differential hardening behavior and tension-compression asymmetry, and its plastic evolution is accurately characterized by the Lou2022 model. The axial crushing properties show that the AA6061-T6 thin-walled rectangular tube undergoes the progressive symmetrical folding deformation mode. The introduction of geometric discontinuity can obviously reduce the peak force and improve the crashworthiness performances under the axial load. The main crushing mode is bending with a small amount of indentation for three-point bending. Moreover, the three-point bending simulation shows that the Lou2022 function considering differential hardening behavior has the highest simulation accuracy. Three different oblique crushing simulations of 10∘, 20∘ and 30∘ illustrate that the AA6061-T6 rectangular tube at 10∘ mainly occurs progressive folding deformation. while the other two oblique crushing angles undergo global buckling deformation. The total energy absorption at 10∘ is 1.87 and 2.43 times of that at 20∘ and 30∘, respectively. The crushing force efficiency of 20∘ and 30∘ is 41.28 % and 31.8 % lower than that of 10∘, respectively. A comprehensive understanding of the energy absorption performance of AA6061-T6 thin-walled rectangular tube under different crushing conditions is helpful to determine its position and shape as a vehicle safety structure, and to exert its optimal plastic deformation potential to dissipate the collision energy and ensure passenger safety.

BIM in Optimization of Power Duct for Efficient Cable Routing: An Industrial Approach

Objectives: This study was conducted to achieve optimized power duct sizes with ensuring sufficient bending for the electrical cables at the road junction locations. Methods: Used Revit tool, a Building Information Modelling (BIM) technology to integrate the design data of electrical cables and for modelling the power duct structure. Tools in the Revit software were used to automate the cable bending and clash detection simulations tasks. Findings: With the help of these tools, we modeled cable routing and optimized power duct structure sizes, saving 90% of man-hours and achieving 20% cost savings at the site compared to conventional methods. Novelty: It’s a pioneering effort to integrate the design data of electrical cables and automate the cable routing by ensuring the sufficient bending radius by utilizing the tools in the Revit software. And optimization of the power duct size at the cable transition locations by performing multiple simulations of the model and clash detection. Keywords: BIM, Revit, Virtual Design, Cable Routing, Electrical Design

Predicting plastic behavior of magnesium alloy tube bending with comprehensive constitutive models

This paper aims to predict defects occurring in magnesium alloy tube bending through finite element simulations. Deformation tests were conducted to identify and characterize plastic anisotropy, tension-compression asymmetry, and anisotropic hardening behaviors of extruded Mg–Al–Zn-RE alloy rectangular tubes. Limited by size, the deformation tests along the wall thickness of specimens were conducted through crystal plasticity analysis. To thoroughly investigate the material constitutive features affecting bending, two constitutive models, Yoon2014 and Hill48, were established and calibrated. The non-associative flow rule was adopted, and anisotropic hardening was depicted using the yield-surface interpolation method. In comparison, the Yoon2014 model accurately predicted the strain distribution and tube shape collapse of the bent tube with negligible deviation from the experimental data, prior to the Hill48 model. This underscores the necessity of considering comprehensive plasticity models in tube bending simulations.

Mechanics of Pure Bending and Eccentric Buckling in High-Strain Composite Structures.

To maximize the capabilities of nano- and micro-class satellites, which are limited by their size, weight, and power, advancements in deployable mechanisms with a high deployable surface area to packaging volume ratio are necessary. Without progress in understanding the mechanics of high-strain materials and structures, the development of compact deployable mechanisms for this class of satellites would be difficult. This paper presents fabrication, experimental testing, and progressive failure modeling to study the deformation of an ultra-thin composite beam. The research study examines the deformation modes of a post-deployed boom under repetitive pure bending loads using a four-point bending setup and bending collapse failure under eccentric buckling. The material and fabrication challenges for ultra-thin, high-stiffness (UTHS) composite boom are discussed in detail. The continuum damage mechanics (CDM) model for the beam is calibrated using experimental coupon testing and was used for a finite element explicit analysis of the boom. It is shown that UTHS can sustain a bending radius of 14 mm without significant fiber and matrix damage. The finite element model accurately predicts the localized transverse fiber damage under eccentric buckling and buckling stiffness of 15.6 N/mm. The results of the bending simulation were found to closely match the experimental results, indicating that the simulation accurately shows deformation stages and predicts damage to the material. The findings of this research provide a better understanding of the structure characteristics with the progressive damage model of the UTHS boom, which can be used for designing a complex deployable payload for nano-micro-class satellites.

Numerical study on the behavior of polypropylene fiber reinforced concrete subjected to moderate temperature variations using LDPM theory

This paper presents the mechanical behavior of macro-synthetic fiber-reinforced concrete with polypropylene fibers (MSFRC) under varying temperature environments. The Lattice Discrete Particle Model (LDPM), a meso-scale model for concrete, is used for the plain concrete study. An extended version of LDPM taking into account the effect of fibers in a discrete way, LDPM-F, is applied for the MSFRC study. The model is calibrated based on the experimental data at room temperature (20 °C). Temperature effects on the MSFRC constituents, fiber and concrete, are individually adjusted inside the LDPM-F formulation based on literature data and available models. Subsequently, predictive three point bending simulations on MSFRC are performed at different temperatures (−30 °C, −15 °C, 0 °C, 40 °C and 60 °C) and the results are validated against available experiments. The results show a generally good agreement between simulations and tests.

Adaptive pneumatic soft gripper with embedded flexible bending sensor

Purpose The purpose of this paper is to introduce a variable distance pneumatic gripper with embedded flexible sensors, which can effectively grasp fragile and flexible objects. Design/methodology/approach Based on the motion principle of the three-jaw chuck and the pneumatic “fast pneumatic network” (FPN), a variable distance pneumatic holder embedded with a flexible sensor is designed. A structural design plan and preparation process of a soft driver is proposed, using carbon nanotubes as filler in a polyurethane (PU) sponge. A flexible bending sensor based on carbon nanotube materials was produced. A static model of the soft driver cavity was established, and a bending simulation was performed. Based on the designed variable distance soft pneumatic gripper, a real-time monitoring and control system was developed. Combined with the developed pneumatic control system, gripping experiments on objects of different shapes and easily deformable and fragile objects were conducted. Findings In this paper, a variable-distance pneumatic gripper embedded with a flexible sensor was designed, and a control system for real-time monitoring and multi-terminal input was developed. Combined with the developed pneumatic control system, a measure was carried out to measure the relationship between the bending angle, output force and air pressure of the soft driver. Flexible bending sensor performance test. The gripper diameter and gripping weight were tested, and the maximum gripping diameter was determined to be 182 mm, the maximum gripping weight was approximately 900 g and the average measurement error of the bending sensor was 5.91%. Objects of different shapes and easily deformable and fragile objects were tested. Originality/value Based on the motion principle of the three-jaw chuck and the pneumatic FPN, a variable distance pneumatic gripper with embedded flexible sensors is proposed by using the method of layered and step-by-step preparation. The authors studied the gripper structure design, simulation analysis, prototype preparation, control system construction and experimental testing. The results show that the designed flexible pneumatic gripper with variable distance can grasp common objects.

Effect of particle size distribution on the cryogenic mechanical properties of triple‐base propellants

AbstractFillers play a decisive role in the mechanical properties of polymer composites. In this paper, different particle sizes of nitroguanidine were obtained to regulate the internal filler structure of triple‐base propellants (TBP) to improve their mechanical response in different environments. A series of morphological and structural characterizations on nitroguanidine (NQ) particles were conducted using techniques. The results indicated that the obtained NQ particles maintained a high level of crystalline quality while preserving their molecular integrity. The mechanical properties of TBP were systematically evaluated under various loading conditions, including cryogenic tensile, compressive, and impact loads, as well as dynamic thermomechanical effects. Additionally, three‐point bending simulations were employed to elucidate the mechanical responses and damage mechanisms. Under axial tensile and compressive loads, reducing the particle size of NQ significantly enhanced the tensile and compressive strength. The maximum tensile strength and compressive strength can reach 344.62 MPa and 104.79 MPa. Moreover, the compressive failure mode transitioned from cracking to axial shrinkage. Conversely, when subjected to radial bending loads, TBP exhibited contrasting behavior, including a decrease in the glass transition temperature from 84.73°C to 76.93°C and a non‐monotonic trend in impact strength (initially increasing from 4.96 to 8.85 kJ/m2 and then decreasing to 2.27 kJ/m2). This study provides valuable insights into the mechanical performance of TBP, supporting the development of high‐energy, high‐strength TBP formulations.Highlights SEM analysis confirms the pronounced orientation effect of rod‐like NQ. The orientation and particle size of NQ decide TBP's radial impact resistance. Submicron NQ enhances the compression resistance property of TBP. Submicron NQ brings about a shift in the microscopic damage morphology of TBP.